The long-term goals of this project are to provide vision professionals with an objective, efficient, and user- friendly instrument that can be used for early detection of visual deficits associated with glaucoma, and for monitoring of visual function quantitatively over time. Phase I funding for this project enabled the successful development of an electrophysiological tool, based on recording the visual evoked potential from the surface of the head, to assess the integrity of select visual pathways known to be affected by the disease process of glaucoma. The goal of the proposed Phase II project is to refine this instrument to serve as a diagnostic screening device for this ophthalmic disorder. Glaucoma affects millions of Americans and it is one of the leading causes of blindness in the U.S. today. It produces a gradual and progressive degeneration of retinal ganglion cells. Unfortunately, by the time this glaucomatous neuropathy is detected, there is typically extensive and permanent damage to the visual system, and profound loss in visual function. Presently, there is a paucity of screening and diagnostic tools available to vision professionals that can aid in the early detection of this disease and in the monitoring of treatments for the purpose of neuroprotection. There is evidence to indicate that select large-cell (magnocellular) pathways in the visual system are affected in an early stage of the disease. We intend to exploit this knowledge in the development of the proposed system. Specific Aims: 1. Improve the performance of the current prototype device through the addition of hardware and software features such as eye movement monitoring and automated noise detection. 2. Evaluate the operation and reliability of the modified device in a multi-center study of glaucoma patients, glaucoma suspects, ocular hypertensives, and age-similar control observers. 3. Develop an equation for prediction of glaucomatous damage from the set of response measures obtained to optimize the accuracy of the screening test.